When the first European settlers set foot in the Americas hundreds of years ago they brought plants and animals from their homeland. Often they brought seeds so that they would be able to grow food. For hundreds of years, people have been introducing new species of plants to the Americas. Often these non-native plants are called â€œexotics.â€ Today, a plant that is considered â€œnativeâ€ to the Americas is one that was already growing naturally in the area before European settlement. Many of the plants that are seen around the U.S. today are not native in this sense. Exotic plants can also be introduced by migratory birds, animals (through their fecal droppings), and via wind and water.
It should also be noted that exotic species are not limited to plants and can take the form of any non-native wildlife including mammals, insects, fish, etc. â€” all of which can become invasive species.
In the global society today, you can order plants from around the world to plant in your garden and yard. Most of the non-native plants that have been imported help create a more diverse environment, add to the beauty of the landscape, or provide valuable food. However, some of these non-native plants do not remain confined to your yard. If the new plant is better at survival and reproduction than the native plants in an area, it can take over. When this happens the exotic plant is called an â€œinvasive speciesâ€ because it invades the new ecosystem and can take over large areas. One reason they may take over is because they may not have any native predators to inhibit their growth. In many cases the invasive species will reduce the diversity of life in an area because it will squeeze out everything else and outcompete for valuable resources such as food and/or water. You can learn more about invasive species at the following resources:
- Source: The United States National Arboretum. (2013). Invasive plants. Retrieved from http://water.epa.gov/type/oceb/habitat/invasive_species_index.cfm
A common example of this is kudzu ( Pueraria montana var. lobata) a plant native to Asia that was intentionally introduced in the late 1800s to help with erosion control (which it does quite effectively). You can learn more about kudzu here:
Source: National Agriculture Library. (2013). Plants. United States Department of Agriculture. Retrieved from http://www.invasivespeciesinfo.gov/plants/kudzu.shtml
During the unit, address the following questions:
- What kinds of problems can invasive species cause? Do you think one group of invasive species is worse than another? Why, or why not?
- Is there one effective way to combat the spread of an invasive species? Can you propose a method?
- Provide some information on an invasive species in your area. You can conduct a quick search on your state using the following website. Be sure to take a look under each category (e.g., aquatic species, animals, etc.):
- Source: National Agriculture Library. (2013). State resources. United States Department of Agriculture. Retrieved from http://www.invasivespeciesinfo.gov/unitedstates/state.shtml.
- If you do not live in the United States, please try to find information on invasive species in your area of the world or you can choose a region of interest to you in the United States.
- How was your chosen invasive species introduced into your area? If a reason was not provided with your resource, please give a hypothesis of how this could happen.
- How has human activity impacted Earthâ€™s natural ecosystems?
- What can you do to help prevent the spread of invasive species?